Diagnostic code 22

[aesc]

Hi,

Over the last month my fuel economy has dropped quite noticeably (50 kms less per 40L) so tonight I checked to see if the diagnostics bought up any codes. Sure enough I pulled code 22 - water temp sensor. Apparently the fault is either the sensor itself, the circuit or ECU (unlikely)

So on a 4AG, is this the green sensor (furtherest one to the passenger side) on the gearbox side of the head?

And is there a way the sensor can be checked before I go and order another one? Is there anything else I should know?

Cheers

[gordon77]

Hi,

Over the last month my fuel economy has dropped quite noticeably (50 kms less per 40L) so tonight I checked to see if the diagnostics bought up any codes. Sure enough I pulled code 22 - water temp sensor. Apparently the fault is either the sensor itself, the circuit or ECU (unlikely)

So on a 4AG, is this the green sensor (furtherest one to the passenger side) on the gearbox side of the head?

And is there a way the sensor can be checked before I go and order another one? Is there anything else I should know?

Cheers

yeah im not sure on the exact readings but pull it out, suspend it in cold water and heat the water up. get a thermometer to measure the hotness, at a certian degree it should change voltage i think.
ill have a look in my smallport manual, cant see why it would be different to your car.

[gordon77]

ok its a graph on the manual but ill list what the resistance at different temps

Degrees l Resistance (ohms)

0 6-8.5
20 2.5 - 3.7
40 1 - 1.8
60 0.6 - 0.75
80 0.27 - 0.45
100 0.1 - 0.25

if it falls outside of this band of resistance to ohms its defective

[Lloyd]

And thats thousand of ohms btw. Just check when cold (20°ish) and it should read around 3000 ohms. Put in fairly hot water and it should be around the 300 mark

[YeMs]

by rights it should run like arse at idle and especially on cold mornings. this is what happened to my cressida, the water temp sensor $&#$% out and it would run like absolute arse, 100% duty cycle the injectors nad it wouldnt run etc, hooked up the interject and it would run on about 6psi of fuel pressure (lol) but yeh replaced the sensor and it made a world of difference. while i waited for my sensor to come in i just bridged the plug (no resistance) and it ran fine.

[aesc]

Thanks for your replies Gordon77 and HRT, I will get hold of a multimeter and check it.

YeMs - doesnt run or drive badly at all, I wouldnt have noticed anything was wrong if the fuel economy was still OK. So itll prob be sweet until the new one arrives

So on a 4AG, is this the green sensor (furtherest one to the passenger side) on the gearbox side of the head?

Can anyone confirm?

[kpimpin61]

yep thats the sensor your after the one with the brown plug is the cold start injector timer

[aesc]

yep thats the sensor your after the one with the brown plug is the cold start injector timer

Cheers, but I'm refering to the temp sensor for the ECU which is the green plug, but yeah think thats the one I need now anyway...

I checked the resistance of both ecu and cold start injector sensors tonight, the ecu sensor seems fine, got a resistance of 320ohms at 80 deg C.
However the cold start sensor gave a 0 reading. Should this be giving similar readings to the ecu sensor?

[RedMist]

No, the cold start sensor is a simple switch.

[aesc]

Hmmm ok then. I took both sensors out in the end and tested them. The ecu sensor seems to be giving readings within the parameters gordon77 specified above. The cold start was also giving readings once I got it out of the car - between 30-60ohms

If this is the case what else could be causing the fault? Thing is the engine check light doesnt come on in normal driving, only when bridging te1 and e1.

Suggestions?

[matt dunn]

Hmmm ok then. I took both sensors out in the end and tested them. The ecu sensor seems to be giving readings within the parameters gordon77 specified above. The cold start was also giving readings once I got it out of the car - between 30-60ohms

If this is the case what else could be causing the fault? Thing is the engine check light doesnt come on in normal driving, only when bridging te1 and e1.

Suggestions?

Clear then codes then drive it for a few days then recheck them.
Check them when you have cleared them before you start the car to make sure they have cleared.

Matt